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author | Gabor Juhos <juhosg@openwrt.org> | 2011-11-13 11:26:52 +0000 |
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committer | Gabor Juhos <juhosg@openwrt.org> | 2011-11-13 11:26:52 +0000 |
commit | 819f6df245417fdc72ad1b3f1b49caf9c417a8bf (patch) | |
tree | 02d1026a16ab6c9e288a8a15ecbe9188e0650889 /rules.mk | |
parent | 003cbe35e26efa7b1df844709a4bdeee8f21624c (diff) | |
download | master-187ad058-819f6df245417fdc72ad1b3f1b49caf9c417a8bf.tar.gz master-187ad058-819f6df245417fdc72ad1b3f1b49caf9c417a8bf.tar.bz2 master-187ad058-819f6df245417fdc72ad1b3f1b49caf9c417a8bf.zip |
ar71xx: fix occasional kernel hangs during boot on AR934x
The patch taken from the linux-mips mailing list.
The Kernel hangs occasionally during boot after
"Calibrating delay loop..". This is caused by the
c0_compare_int_usable() routine in cevt-r4k.c
returning false which causes the system to disable
the timer and hang later. The false return happens
because the routine is using a series of four calls
to irq_disable_hazard() as a delay while it waits
for the timer changes to propagate to the cp0 cause
register. On newer MIPS cores, like the 74K, the
series of irq_disable_hazard() calls turn into ehb
instructions and can take as little as a few clock
ticks for all 4 instructions. This is not enough of
a delay, so the routine thinks the timer is not
working.
This fix uses up to a max number of cycle counter
ticks for the delay and uses back_to_back_c0_hazard()
instead of irq_disable_hazard() to handle the hazard
condition between cp0 writes and cp0 reads.
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@29009 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'rules.mk')
0 files changed, 0 insertions, 0 deletions